Does this perhaps belong in the clinic
Mate. Black is such a generalisation. In reality you have black people in East Aftica who have over years evolved differently from black people in west africa. Many people from various tribal islands would pass as black. Theyve been independent from the rest of Africa for millenia.
You have US basketball players who are minimum 196 cm. Half of them are 210 cm +. Then you have pygmy people who are maximum 150 cm.
The Kenyans from the mountains - Kalenjin people who excel at 3000m are generally taller. The etheiopians who do 10000m and marathons are smaller. Haile and Kenenisa are both 165.
So some black people are more naturally muscular. Some less. There are huge differences.
But think that these marathon runners, would be excelent climbers. They have very slim bodies. They have very high endurance. Bekele has amazing speed as well, so perhaps good enough in tts for gt contender.